Block-signal system.



v No. 829,783.

PATENTED AUG. 28, 1906,. M.R.HANNA. BLOCK SIGNAL SYSTEM.

GATION FILED MAR.10.1905.

APPLI In ventori Witnesses.

Max RI-lanna.

4/ %.Qz4., KSZW -feulty bonding an alternating current ex- UNITED srecrnfs PATENT MAX R. HANNA, OF SCHENEOTADY, NEW YORK. ASSlGNOlt TO GENERAL -ELEOTRlC COMPANY, ,A CORPORATION OF NEW YORK.

BLOCK SiGNAL system;

Specification of Letters Patent.

Patented Aug. 28, 1906.

Application filed March 10, 1905. Serial No. 249.375,

To aZZ whom it may concern:

Be it known that 1, MAX R. HANNA, a citizen of the United States, residing in Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Block-Signal'Systems, of which the followin :is a specification.

My inventionreates to block-signals for electrically-operated railways in which the driving-motors are supplied'with alternating current. When relays of the ordinary t pe; are employed for the signal systems of e co trically-operated roads, trouble is likely to arise from the fact that leakage of power-: current operate the relays so as to give a clear indication. when a train is in a block.

My invention consists, in. the combination, with an altenating-current railway system employing the rails as a return-conduce tor, of a direct-current signal s stem comprising a novel form of relay whic is responsive to direct current only, and consequently cannot be affected by leakage from the alternating-current power-circuit. For this purpose I employ a relay of the wattmeter or dynamometer type comprising two relatively movable coils. One of these coils I connect to the track-circuit, while the other is supplied with direct current independently of the track-circuit.

Since the operation of the relay depends upon the reaction of the currents in the two coils upon each other and since an alterns mg current in one coil acting upon a direct current in the other can produce no torque,

an alternating current in the track-circuitcoil leaking from the power-circuit can have no effect upon the di coil. 7

Since the rails are employed as return-conduct rs forthe power-circuit, a large alternating current flows through the rails, and consequently under certain conditions of cessive in amount as compared with the normal relay-current may flow through the rel&"COlltl18t1S connected to the track-circuit.

If this large alternating current in the stationarycoil should induce an alternating current in the movable coil, the two alternating currents would react on each other, producing a torque in the same Way that a torque is produced in the well-known repulsion-motor. With large alternating currents flowing a negligible amount. rectcurrent in the second through the stetionarycoil this torque might be great enougltto interfere with the operation of the relay, either causing it to set the signal at clear when it should be at danger, and thus rendering accidents possi- -ble,or causing it to set the signal at dunger when it should he at clear, and thereby unnecessarily delaying traffic. In order to prevent absolutely any possibility of a repul sion-motor action, due to the leakage of power-currenhwcausing the relay to give a clear signal at the wrong time, I so arrange the two relay-coils relatively to each. other that the movable coil in moving to its danger position moves in the direction of the tor ue, due to the repulsion-motor action.

this arrangement it is absolutely impossible that a leakage of power-current through one coil of the relay should produce a false clear indication of the signal, although -.it might-hold the relay in danger position 5 when it should move to clear position, thereby delaying traffic. I have, however, provided means for overcoming this objection by providing an arrangement for reducing the repulsion-motor action under any conditions to a negligible amount. I accomplish this by mounting short-circuited conductors on the magnetic circuit between the stationary. and movable coils which act to screen the al-- ternuting-current .fiuX due to leakage of ower-current in one coil from the other coil.

ith this arrangement practically no alternating current can ever be induced in the movable coil, so that all repulsion-motor action is substantially eliminated or reduced.- to

The most eificient operation of the relay and the greatest torque are obtained. when the movable coil is mounted on e magnetic core, and accordingly I provide a movuhle core for carrying the movable coil and so enrange this core that the reluctance of the magnet c circuit of the relay is the same for all positions of the core.

My invention will best be understood by reference to the accompanying drawings,- in which, Figure 1 shows, somewhat diagrammatically, a block-signal system arranged. in accordance with my invention, and Fig. 2 shows a plan view or the relay.

In the drawings, R represents one rail of the track, which is shown continuous so as to serve as a return-conductor for the power- ,Ineclianism. F or the sakeof simplicity l ill sents the tinrrl. rail or troll ing power-current to the car conductor is shown energizeil iron iugcurrent generator A. trace-circuits are supplied Witl'i ourrentircn the usual trackbatteries, two of these batteries B and B beiiig shown in the drawings. These batteries are connected to one end of each block, while to the other end of each block is connected one coil of the relay for controllingthe signal for that block. Twosignals S and S are s11 VH1 at near the entrance to the blocks Rancl respectively. These signals are provided with any suitable form of operating;

have shown the operating mechanism con sisting of simple solenoid H", arranged when energized to draw the signal to clear position and when deenergizerl to allow the signal to be drawn to Niaoger by its coon-- terweight. The solenoid H. is supplied from any suitahle'souroe of current, either direct or alternating, (indicated by the battery 75'.) It will be understood that while for the sake of simplicity I llfi-T shown a simple solenoid for operating the signal, any Well-known form of driving mechanism maybe employed. The circuit of the operating mechanism for the signal comprises two contacts 0, which are adapted to be bridged by a contact-arm C of the relay 7'. This relay comprises two relatively movable coils. The stationary or i'ielrl coil f is shown connected across the rails i3. and R, and consequently is supplied with direct current from the traclr battery at the other end. of tlie blocir. The movable or armature soil at is mounted rotatably on a magnetic core g and is energized from a source of direct current (indicated by the battery 3)) independently of the traclrci.rcuit. The two coils of andf are so connectedto their respective batteries that the batterycurrent in the coils prorluces a torque which tenils to maintain the arms C in engagement with the contacts 0, and consequently to ll-Old the signal S at clear position, as shown, as long as both are traversed by direct current. If a car or train enters one of the blocks, as is indicated in the block R the re lay-coil), connected to the trafol r-circuit of that clock, is sliort-oii'cuited anti-the contactarm C is drawn away irointhef'ocntacts against the step d by a E fin by grew The circuit ol tlie 'oneieting mechanism of the is thereby opener 8 1 10%" H w; the SL2 Utl to go to "rle er, so as to i The only effect that it can produce is to a sist the normal movement of the relay toward. danger position. V

LZ ince under certain. circumstances a large alternating current frointliepoWercircuit might leak through a coil when no car was in the block, it is desirable that'tlie effect of alternating current upon the relay should. be at all times exceedingly small, since otherwisetlie relay might be held in its-danger position when no car was in, the block and would thereby delay trailic ininecessarily. In order to eliminate substantially all effect of the alternating current upon the relay, i provide slicrt-circniting conductors 6, surrounding poles of the stationary portion of the magnetic circuit. These slio:-:'t-circuiterl conductors act as flux-screens, tending to prevent the passage of any appre ciable amount of alternating flux through tl ino'rable core. These conductors are preferably close to the armature and some distenee froin the field-coil. seas to prevent the alternating flux from passing through the armature and. to permit it to leak through the air between the parts of the fielrl-Qore'on opposite sides of the fielrl-coil Consequently no alternating current of any appreciable amount can ever be induced in the niova cle coil, and even in tlie clear position of the relay'witli a corn aratively large flow oi can rent through tr e stationery coil the operation of the relay is ai'lecteci to a negligible degree. i

In order to secure the most efficient operation and the highest torqueitis essenti that the moi/able coil should be mounted. A magnetic core; but if a magnetic core is 8311* ployed which l yxits movement produces a ariation of the reluctance of the magneticcircuit of the relay torque may be produced due to this cause which may have a disturl ing ei'iect on the action oft-he relay. Consequently I arrange the mov able magnetic core g, as shown in Fig, with eve slots all the Way around the cor men being arr-o ed on a spiral. With this a rang unent e i. tie reluct; ic of the r ova-ole core iii-inc on any dian'ieter, d so, altlio'ugli if a o tion. of the clots A oycgi for o; in novaole cc' toe remaine er of the e ote serve, sinful one making the nioval'ile core entirely orical with respoi'r-t to itsrelnctence.

It will be understood that for the sake of simplicity I have shown my invention somewhat (liagrammatical-ly and that in practice any well-known forms of apparatus may be employed in carrying out my invention. Accordingly I do not .desireto limit myself to the particular construction-and arrangement of parts here shown, but aim in the appended claims to cover all modifications which are within the scope of my invention.

\Vhat I claim as new, and desire to secure by Letters Patent of the United States, is

1. In combination with an alternating-current railway system employing the rails as return conductor for the power current, a direct current signal system comprising means for supplying direct current to the track-circuits, relays each comprislng two relatively movable coils, one connected to the track-circuit and the other supplied with direct current independently of the track circuit, and signals controlled by the relays.

2. In combination with an alternating-mm rent railway, system employing the rails as return-conductor for the power-current, a dir ct-current signal system comprising means for supplying direct current to the track-circuits, relays each comprising two means for supplying direct current to 'the' track-circuitsa relay comprising astationary coil connected to, the track-circuit and a movable coil supplied with direct currentindependently of the track-circuit, a contactarm carried by the movable relay-coil, and a signal controlled by.said contact-arm.

4. In combination with an alternating-current railway system employing thera'ils as return-conductor for the power-current, a

. direct current signal system Tcomprising means forsupplying direct current to the track-circuits, a relay comprising a stationary coil connected to the track-circuit and a movable coil supplied with direct current independently of the track-circuit, a contactarm-carried by the movable relay-coiland arranged to close and open an electric circuit, the movement of said arm to open said' circuit being toward the position in which the movable coil lies parallel to the flux produced by the stationary coil of the relay.

5. In combination with an alternating-current railwa system employing the rails as return-com uctorrfor the power-current, a directcurrent .signal system comprising means for supplying direct current to the trackrcircuits, a relay comprising two relatively movable coils, one connected to the rails of a block and tlte'other supplied with direct current independently of the track: circuit, anda signal controlled by the movement of the movable relay-coil, the movement of said coil to produce a movement of said signal to danger being toward the position in which said movable coil lies parallel to the flux produced by the stationary coil of the relay. 6. In combination with an alternating-current railway system employing the rails as return-conductor for the power-current, a direct-current signal system comprising means for supplying direct current to the track-circuit, and a relay comprising two relatively movable coils, one connected to the track-circuit and the other supplied with direct current independently of the trackcircuit, and a short-cirmiiterlconductor in inductive relation to the coil connected to the track circuit and adapted and arranged to screen a flux due to alternating current in said coil from the second coil.

7. In combination with an alternating-current railway system employing the rails as. return-conductor for the power-current, a

direct-current signal system comprising means for supplying direct current to the track-circuit, and a relay comprismg a stationary field member, a coil thereon con nected to the track-circuit, a second coil movably supported between the-poles of said field member and supplied with direct current independentlyv of the track-circuit, and

IIO

nected to the track-circuit, a, second coil movably supported between the poles of said field member and supplied with direct current independently of the track-circuit,

and short circuited conductors surrounding said field member at points between said stationary coil and'the pole-faces of said member. i

9. In a relay, a stationary field member, an energizing-coil therefor, a uniformly-slotted core rotatably mounted between the oles of said field member, a winding carried by said core and occupying a portion only of said slots, and a contact-arm carried by said core.

10. In a relay, a stationary field member, an energizing-coil therefor, a magnetic core rotatably mounted between the poles olsaid field member and provided with uniformly spaced spirahslots, a coil carried in aportion of said slots, and a contact-arm carried by said core.

11. In combination with an alternatingcurrent railway system employing the rails as return-conductors for the power-current, a direct-current signal system comprising means for supplying direct current to the track-circuits, relays each comprising two cooperating coils, one connected to the trackcircuit and the other supplied'with direct current independently of the track-circuitfand signals controlled by the relays.

12. In comhination with an alternatingcurrent railway system employing the rails as retnrn-conductors for the power-current,

a direct-current signal system comprising means for supplying direct current to the track-circuits, relays each comprising two cooperating coils, one connected to the trackeircui t and the other suppliedwith direct current independently of the track-circuit, movable contacts controlled by the oint action of said. coils, and signals controlled by said contacts.

' In witness whereof 'I have hereunto set my hand this 9th day ofMarch, 1905.

- MAX R. HANNA. Witnesses: BENJAMIN B. HULL, HELEN ORFORD. 

